In general, a side key of a mobile terminal is installed in at least one side of a main body of the mobile terminal. The side key is a key for enabling the mobile terminal to send a signal through manipulation and to execute a desired function.
Typically, side keys of mobile terminals can be classified as either a dome switch type or a tact switch type.
The dome switch type side key attaches a dome sheet that includes a dome switch therein to a flexible printed circuit board (FPCB) and solders the FPCB to a connection terminal, i.e. a row and column terminal pad formed in a main circuit board. For the dome switch, a rubber dome switch or a metal dome switch is used.
The tact switch type side key solders and connects a tact switch element to a row and column terminal pad formed in a main circuit board.
Typically, the tact switch uses surface mount devices (SMD) to which surface mount technology (SMT) is applied.
However, when the dome switch is used, an FPCB for attaching a dome sheet is manufactured, and the FPCB is soldered to the main circuit board. In order to fix the FPCB, a fixing support is provided at a side surface of the main circuit board and is fixed by a double-sided tape.
When the tact switch is used, the tact switch is surface mounted to the main circuit board to correspond to the quantity of the side keys.
For such dome switch type side keys, a FPCB is expensive, the dome switch type side key includes many assembly processes, and the main circuit board occupies much space for the FPCB. For tact switch type side keys, a tact switch and surface mounting are expensive, and the main circuit board may increase the thickness of the mobile terminal by a thickness of the tact switch.